Ewan McGregor has said that the script never named his character, so in his head, his character name was Gordon McFarquor. The credits simply list him as The Ghost. (The character is never named in the original novel.)
Some part of the movie was filmed on the German island of Sylt as a stand in for Martha's Vineyard. To look more American it was dressed up with an attention to details: American style cars, US signage, added telephone poles (phone and energy lines run mostly underground in Germany), wooden houses, American extras, etc.
Writer Robert Harris is a former BBC TV reporter and political columnist who actively supported Tony Blair until the Iraq War, which Harris felt was a mistake. Blair resigned June 26, 2007, spurring Harris to drop his other work to write The Ghost, which was published Sept. 26. Similarities between Blair and Adam Lang, Cherie Blair and Ruth Lang, Hatherton and Halliburton, etc., are clearly intentional. Mo Asumang appears briefly as a Condoleezza Rice look-a-like Secretary of State in a photo op with Lang.
When Roman Polanski was arrested September 2009 in Switzerland, post-production was never put on hold. He saw every step of the film and made all artistic decisions. He finished editing the movie while in a Swiss prison. In December 2009 Polanski was released on bail but placed under house arrest, where he remained when this movie was released.
Was originally filmed as a R rated thriller but upon its purchase for US distribution, it was needed to be cut down to PG-13 to ensure a wider audience. This was done by cutting out 18 F-words, 3 C-words, and also some more graphic sexual dialog as well as trimming some CGI blood spray during a death scene.
The NHL hockey game that The Ghost watches (or pretends to watch) on the TV in the hotel bar is between the Vancouver Canucks and St. Louis Blues on January 23, 2008. The voice of announcer Jim Hughson can clearly be heard on the CBC broadcast, naming such Canuck players as Markus Näslund, Mattias Öhlund, Henrik Sedin and Daniel Sedin.
Although the studio advised the stars to avoid commenting directly on the arrest of Roman Polanski, Pierce Brosnan said during a promotional interview, "It's sad for all concerned, but it's also heightened the movie. The movie's in the can, he's in the can."
Early in the movie, The Ghost passes through a security check and jokingly asks if the company thinks Random House will bomb them. Random House was author Robert Harris' publishing house when he wrote the original novel.
When investigating Professor Paul Emmett's background, the Writer comes across a website talking about investigations into the CIA. A picture depicting two politicians, Frank Church (holding a pistol) and John Tower, is shown. Frank Church was a U.S. senator from Idaho and established a committee named after himself to investigate abuses committed by U.S. intelligence agencies.
Even though he'd won the Silver Bear award as Best Director, Roman Polanski was not permitted to attend the Berlin International Film Festival due to his being under house arrest at his home in Gstaad, Switzerland.
On the fence outside of Professor Paul Emmett's house, a sign reads "Cyclops Security". The Ghost is able to take a peek at Emmett's letter, because there is only one security camera. This is a reference to the cyclopes of Greek mythology.
The trivia item below may give away important plot points.
Adam Lang's (Pierce Brosnan) career and his memoirs bear several parallels (intentional or otherwise) with real-life world leaders. Lang's career is a thinly veiled analogue of that of Tony Blair. The title of Lang's autobiography, "My Life," is the same as that of U.S. President Bill Clinton. The circumstances of Lang's assassination just prior to the release of a scandalous memoir are very similar to that of Pakistani Prime Minister Benazir Bhutto who was murdered just before the release of a book highly critical of certain other political figures. The conspiracy to elect Lang, orchestrated by his wife and the CIA, resembles allegations often leveled against political wives (notably Barbara Bush, Hillary Clinton and Elizabeth Edwards) by conspiracy theorists.